The present invention relates to a lubricant base stock, a lubricant composition, a method of lubricating an object and the use of a lubricant base stock. The lubricant base stock comprises a first ester which is the reaction product of: a first polyol comprising at least 3 hydroxyl groups; a first mono-carboxylic acid comprising from 4 to 18 carbon atoms; and a poly-carboxylic acid comprising at least 2 carboxyl groups and comprising from 20 to 60 carbon atoms. The lubricant base stock also comprises a second ester which is the reaction product of: a second polyol comprising at least 3 hydroxyl groups; and a second mono-carboxylic acid comprising from 4 to 18 carbon atoms.